1. Field of the Invention
The present invention relates to an electronic camera and, more particularly, to a high-image quality electronic camera which allows character recognition and the like.
2. Related Background Art
Conventionally, in order to input characters written on an original or the like into a computer, for example, an image scanner using a linear photoelectric conversion element is used for inputting the character images.
In this case, in the input operation, the original written with the characters is horizontally held by being pressed against the surface of a transparent member such as a glass plate.
Image signals obtained in this manner are subjected to character recognition processing using a hardware arrangement such as a computer having a character recognition processing function or a software program having a character recognition processing function.
Also, a method in which a video signal obtained from a camera is input to the above-mentioned computer having the character recognition processing function and is subjected to character recognition processing has been proposed.
When the character recognition processing is performed based on a video signal obtained from the camera, as described above, if an object to be photographed is not parallel to an image pickup surface, an in-focus state cannot be attained on the entire area of the object to be photographed.
In order to solve such a problem, a method of adjusting an optical system using a tilt mechanism such as a tilt and shift mechanism to attain an in-focus state on the entire area of the object to be photographed even if the object to be photographed is not parallel to the image pickup surface has been proposed.
However, when an object to be photographed written with characters is to be photographed using a camera, it is difficult to attain an in-focus state on the entire surface of the object to be photographed. For this reason, the photographing operation is performed using a base, stand or the like for fixing the object to be parallel to the image pickup surface. This method is inconvenient since it requires a cumbersome operation of setting the base or stand for fixing the object and the camera, and it renders the photographing apparatus bulky.
With the above-mentioned method, an object to be subjected to the photographing operation for performing character recognition is limited to one that can be placed under the base, such as a paper sheet. Therefore, it is difficult to photograph an image of a signboard such as a directional sign, road sign, or the like, a large object or an immovable object such as a plate attached to an industrial product, or a three-dimensional object.
As described above, an in-focus state can be attained on the entire object or an image distortion can be eliminated using an optical system having a tilt mechanism such as a tilt and shift mechanism even when the image pickup surface is not perpendicular to the object. However, the tilt mechanism cannot be easily operated since it requires skills in adjustment.
An electronic camera which automates adjustment requiring skills has also been proposed. However, such a camera has a high cost since it requires a complicated mechanism and a complicated control.
The present invention has been made in consideration of the above situation, and has as its first object to provide an electronic camera which can realize a high-image quality photographing operation.
It is the second object of the present invention to provide an inexpensive electronic camera which can easily attain character recognition.
It is the third object of the present invention to provide an electronic camera which can realize accurate focus adjustment on the entire image pickup surface.
In order to achieve the above objects, according to a preferred embodiment of the present invention, there is disclosed an electronic camera comprising image pickup means for converting an object image formed on an image pickup surface into an electrical signal, focusing means for forming the object image on the image pickup surface, focus detection means for dividing the object image formed on the image pickup surface into a plurality of portions, and performing focus detection for the plurality of portions, focus adjustment means for adjusting the position of the focusing means on the basis of outputs from the focus detection means, and display means for displaying focus detection information of the plurality of portions detected by the focus detection means.
According to a preferred embodiment of the present invention, there is disclosed an electronic camera which further comprises tilt correction information generation means for generating tilt correction information used for setting the image pickup surface of the camera to be parallel to a planar object on the basis of results obtained by the divisional distance measurement operations of the focus detection means, and displays the tilt correction information on the display surface of the display means.
According to a preferred embodiment of the present invention, distance measurement information at each of a large number of points obtained by the divisional distance measurement operations of the focus detection means can be displayed in a finder. With this information, a user can confirm, during a photographing operation, whether or not an in-focus state is attained on the entire object with respect to the image pickup surface. Thus, a photographing failure when an in-focus state is not attained on the entire object can be prevented.
It is still another object of the present invention to provide an electronic camera which can notify a photographer of the current tilt direction of the camera during a photographing operation so as to allow the photographer to perform easy tilt adjustment, and can easily set an in-focus state on the entire object.
Other objects and features of the present invention will become apparent from the following specification and the accompanying drawings.